The invention relates to a method for the making of an optoelectronic device such as a laser diode or a photodetector and, more particularly, a device in ridge form.
The methods generally used to make diodes and arrays of laser diodes suffer the drawback of a cumbersome technology that comprises a large number of elementary steps. For example, the ridge structure commonly used and shown schematically in FIG. 1 calls for:
two epitaxy steps;
one lithography/etching step;
one ion or proton implantation step.
The techniques of epitaxy in ultra-vacuum such as those of the molecular beam epitaxy (MBE) or chemical beam epitaxy (CBE) type are opening up new possibilities in terms of selective epitaxy. The molecular nature of the fluxes in MBE and CBE offer the possibility of selective growth through a mechanical mask placed on the substrate. Moreover, it is only these techniques that enable the growth of semi-insulator III-V materials such as, for example, GaAlAs, InP or GaInP.
For example, the article by W. T. TSANG et al, "Selective Area Growth of GaAs/Al.sub.x Ga.sub.1-x As Multilayer Structures With Molecular Beam Epitaxy Using Si Shadow Masks" in Applied Physics Letters, Vol. 31, No. 4, Aug. 15, 1977 describes a method of epitaxy through a mechanical mask. However, no method for the manufacture of optoelectronic devices uses this technique which, all the same, is a known one.
The invention relates to a method for the making of ridge type optoelectronic devices that comprises a reduced number of manufacturing steps. In particular, this method has the advantage of requiring only one epitaxial step.